Research of multi-pulses emission in passively Q-switched Nd3+:YAG microchip laser

Multi-pulses emission in the passively Q-switched microchip Nd3+:YAG/Cr4+:YAG laser was studied. The pulses include a main pulse and several satellite pulses. The width of the main pulse was 3.6 ns under the pump power of 14.78 W, corresponding to a pulse repetition rate of 7.89 kHz. The spectrum of pulses varying in different pump power was analyzed. Multi-longitudinal-modes oscillation was observed. Experiment result shows multi-pulses emission is related with multi-longitudinal-modes oscillation.